In conventional electrical circuits, current sources are often essential to a circuit design. One especially useful form of a current source is a voltage-controlled current source, in which the output current is dependent upon an input differential voltage. Depending on the application, a current source may be required to support dramatically different loads. That is, the current source may be required to operate at a high current output level for one time period, then operate at a low current output level for another time period. Conventional voltage-controlled current sources that operate to source a wide range of current levels generally are designed to include a large standby current to support the large current output required during high output modes (cycles). In these applications, the large standby current must be maintained even if the output current is low. A high standby current may result in an inefficient use of power, and also may cause undesirable heating.